A catheter is a hollow tubular instrument which is inserted into the human body from the outside. A catheter may be used to inject a liquid into the body or to extract humor, or it may be is used for maintaining an open state of a passage, and so on.
A catheter having a spherical rubber plug (balloon) attached to its extreme end is popularly used to effect hemostasis (i.e. used to effect the arresting of circulation of blood in a blood vessel which is hemorrhaging). It is inserted into the body to a side of a bleeding internal body portion, for example, a portion of intracerebral hemorrhage which side of the bleeding internal body portion is the side closer to the heart. A thermosetting resin is injected into the spherical rubber plug on the extreme end to expand the plug and to thereby stop flow of blood in the blood vessel. In this case, in order to leave the expanded plug portion on the extreme end of the catheter in the blood vessel which is used to stop the discharge of blood, the expanded plug of the catheter is softened and cut off by heat. The heat is generated by supplying a high-frequency electric current carried by leadwires to electrodes which are located on the end portion of the catheter. In the case of this type of catheter, it is necessary for the catheter to have a cut portion through which leadwires are led out. The leadwires connect the electrodes with a high-frequency current generator. Since the thermosetting resin is injected into the plug of the catheter through an injection tube under pressure, a pressure proof connector is used on the cut portion of the catheter to connect the catheter and the injection tube.
The construction of a prior art connector is as shown in FIG. 2. An elastic tube 5 (silicone tube) is used to connect catheter 1 which has a diameter of 1.2 mm, and is made of Teflon which is poor in adhesion, with injection tube 4 made of the same material. For improvement in bonding strength of the connections, thereby ensuring resistance to a pressure of 15 atm at the maximum instantaneous adhesive 10 having an interfacial effect and having a low viscosity of about 5 to 10 centiPoise is applied to surfaces of the catheter, the injection tube and the elastic tube, and then epoxy adhesive 6 is applied thereon two or three times. Leadwires 3, extending from the electrodes, are led out through a gap between the elastic tube and the injection tube and are connected to the high-frequency current generator by alligator clips.
In this conventional connector, the instantaneous adhesive 10 applied to the surfaces of the catheter, the injection tube and the elastic tube has a low viscosity and is therefore poor in affinity with hard epoxy resin 6 forming the upper layers, and the connector may be deformed if an excessive pressure is applied and if the strength of the epoxy resin is insufficient. There is therefore a risk of formation of a gap and, hence, occurrence of liquid leakage. Thus, the conventional connector entails the problem in terms of being pressure proof. It also entails the problem in terms of reliability owing to the risk of disconnection of the leadwires or the risk of alligator clips coming off since the leadwires are made of fine copper wires having a diameter of 0.05 mm and are connected by the alligator clips.